US20120070788A1

US20120070788A1 - ECCENTRIC JET TYPE LOW NOx OXYFUEL BURNER

Info

Publication number: US20120070788A1
Application number: US12/885,670
Authority: US
Inventors: Dong-Soon Noh; Eun-kyung Lee; Chang-Bok Ko
Original assignee: Korea Institute of Energy Research KIER
Current assignee: Korea Institute of Energy Research KIER
Priority date: 2010-09-20
Filing date: 2010-09-20
Publication date: 2012-03-22

Abstract

Disclosed is an eccentric jet type low NO_Xoxyfuel burner for gaseous fuel, which freely controls the shape of a flame and a combustion characteristic by using an eccentric injection nozzle. The disclosed oxyfuel burner reduces an optimum mixture rate forming area in comparison with a conventional coaxial-injection, and enlarges a thin fuel area and an excessive fuel area so that partial generation of a flame with a high temperature is restricted. Therefore, an amount of generated nitrogen oxide can be minimized and the stability of a flame can be significantly improved. Particularly, the oxyfuel burner combines a fuel nozzle and an oxygen combustion nozzle having different diameters so as to use them so that it is very simple and practical to design and manufacture the oxyfuel burner.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a low NO_Xoxyfuel burner, and more particularly to a low NO_Xoxyfuel burner for gaseous fuel, which can freely control the shape of a flame and combustion characteristics and uses oxygen of low purity.
2. Description of Related Art
An oxyfuel burner applied to thermal equipment used for industrial and commercial purposes requires a high combustion efficiency, and a performance which minimizes the generation of pollutants and achieves variable and stable flame characteristics, as well as structural simplicity and endurance.
A conventional low NO_Xoxyfuel burner performs a method for dividing and injecting oxygen or fuel in a multistage manner and has spatially various mixture rates according to each division rate.
In other words, the conventional oxyfuel burner divides fuel and oxygen into fuel at low concentration and oxygen at high concentration or into oxygen at low concentration and fuel at high concentration so as to mix them, thereby partially lowering the highest temperature of flame.
In general, a low NOX oxyfuel burner uses oxygen of high purity or expands a thin fuel and excessive fuel mixture area through oxygen division or fuel division high-speed injection, thereby partially lowering the highest temperature of flame.
Also, in order to secure the stability of the flame, a low NOX oxyfuel burner requires propriety in an injection speed, propriety in a division rate, a structural design in the shape of a nozzle outlet, etc. and optimization in manufacturing.
The oxyfuel burner performing the above described combustion method has to be controlled in operation thereof so as to maintain an optimized performance because generation of nitrogen oxide (NOX) and stability of the flame are influenced by the shape of a nozzle outlet and a division rate as well as the temperature of an atmosphere and oxygen so that the performance is changed.
Meanwhile, in a case of a low NOX oxyfuel burner performing combustion by directly injecting fuel at high speed, the high-speed direct-injection of fuel is impossible at an early stage of operation, because a temperature is low so that flame stability and combustion efficiency are low due to the structure of a nozzle. Therefore, in order to maintain high combustibility and a stable flame until the temperature of the atmosphere reaches a predetermined temperature, it is required that a nozzle has a structure performing a function of mixing fuel with oxygen.
Herein, such a flame range of a high temperature inevitably expands so that a nitrogen oxide can be excessively generated. Therefore, in order to prevent this, the shape of a nozzle of a burner may be complicated and there is a difficulty in manufacturing and assembling.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and the present invention provides an oxyfuel burner, which can maintain the stability of a flame under the operation atmosphere of a low temperature regardless of injection-speeds of oxygen and fuel, freely control the shape of the flame and a combustion characteristic, and minimize the generation of a nitrogen oxide even if oxygen of low purity including nitrogen is used, or an atmosphere has a large amount of nitrogen due to the penetration of outer air.
In accordance with an aspect of the present invention, there is provided an eccentric jet type low NOX oxyfuel burner for gaseous fuel, including: an oxygen combustion pipe inserted within a burner tile so as to be concentrically positioned respective to a central axis of the burner tile, the oxygen combustion pipe including an oxygen feeding pipe connected to one side portion of a circumferential surface of the oxygen combustion pipe so that oxygen is supplied through an oxygen feeding inlet provided at one end of the oxygen feeding pipe, and an oxygen combustion nozzle for injecting the supplied oxygen, provided at one end of the oxygen combustion pipe; and a fuel combustion pipe inserted within the oxygen combustion pipe so as to be concentrically positioned respective to a central axis of the oxygen combustion pipe, the fuel combustion pipe including a fuel feeding pipe connected to one end of the fuel combustion pipe so that fuel is supplied through a fuel feeding inlet provided at one end of the fuel feeding pipe, and a fuel combustion nozzle provided at a same side as the oxygen combustion nozzle so as to inject fuel at a position deviating as much as a certain multiple of a set measurement from a central axis of the oxygen combustion pipe.
Herein, the fuel combustion pipe may rotate about a central axis of the oxygen combustion pipe. The oxygen combustion pipe may be inserted into the fuel combustion pipe according to the above-described scheme.
The oxyfuel burner according to the present invention reduces an optimum mixture rate forming area in comparison with a conventional coaxial-injection, and enlarges a thin fuel area and an excessive fuel area so that partial generation of a flame with a high temperature is restricted. Therefore, an amount of generated nitrogen oxide can be minimized and the stability of a flame can be significantly improved.
Particularly, the oxyfuel burner according to the present invention combines a fuel nozzle and an oxygen combustion nozzle having different diameters so as to use them so that it is very simple and practical to design and manufacture the oxyfuel burner.
Also, the oxyfuel burner flame can achieve a flame of various shapes and a combustion characteristic according to the rotation of a fuel combustion nozzle (or an oxygen combustion nozzle), thereby flexibly functioning as a low-pollution heating control apparatus applied to a thermal process in various industries.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a cross-sectional view illustrating an eccentric jet type low NOX oxyfuel burner for gaseous fuel, according to the present invention;

FIG. 2 is a left side perspective view illustrating an oxyfuel burner according to the present invention;

FIG. 3 is a right side perspective view illustrating an oxyfuel burner according to the present invention;

FIG. 4 is a left side cross-sectional view illustrating an oxyfuel burner according to the present invention; and

FIG. 5 is a right side cross-sectional view illustrating an oxyfuel burner according to the present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The present invention includes a fuel combustion pipe and an oxygen combustion pipe which have diameters different from each other respectively, and one combustion pipe is inserted into the other combustion pipe so that the one combustion pipe can rotate about a central axis of the other combustion pipe. Therefore, a mixture rate between oxygen and fuel can be freely controlled by an eccentrically provided nozzle of the one combustion pipe so that various combustion characteristics can be achieved.
The eccentric jet type low NO_Xoxyfuel burner for gaseous fuel, according to the present invention, includes an oxygen combustion pipe and a fuel combustion pipe.
The oxygen combustion pipe is inserted within a burner tile so as to be concentrically positioned with respect to the central axis of the burner tile, includes an oxygen feeding pipe connected to one side portion of the circumferential surface thereof so that oxygen is supplied through an oxygen feeding inlet provided at one end of the oxygen feeding pipe, and also includes an oxygen combustion nozzle for injecting supplied oxygen, provided at one end thereof.
The fuel combustion pipe is inserted within the oxygen combustion pipe so as to be concentrically positioned respective to the central axis of the oxygen combustion pipe, includes a fuel feeding pipe connected to one end thereof so that fuel is supplied through a fuel feeding inlet provided at one end of the fuel feeding pipe, and also includes a fuel combustion nozzle provided at the same side as the oxygen combustion nozzle so as to inject fuel at a position deviating as much as a certain multiple of a set measurement from the central axis of the oxygen combustion pipe.
The fuel combustion pipe can rotate about the central axis of the oxygen combustion pipe within the oxygen combustion pipe. The fuel combustion pipe is rotated by a rotating flange provided at one end of the oxygen combustion pipe.
Herein, the center of the fuel combustion nozzle provided at one end of the fuel combustion pipe while deviating from the center thereof rotates about the central axis of the oxygen combustion pipe so that the mixture of oxygen and fuel which are injected from the oxygen combustion nozzle and the fuel combustion nozzle, respectively, can be freely controlled.
In other words, as the fuel combustion pipe rotates, the injection direction of fuel injected through the fuel combustion nozzle can be controlled, so that it is possible to effectively heat an object according to the position of the object to be heated. Particularly, the shape of the flame can be controlled so as to allow a flame area having radiation heat transmission efficiency to approach an object to be heated or to turn toward the object. Therefore, the oxyfuel burner can be employed as a low NOX oxyfuel burner in a high temperature heating process such as heating steel.
As such, the oxyfuel burner according to the present invention can be operated in a case where the fuel combustion pipe is inserted into the oxygen combustion pipe. On the other hand, it can be also operated in a case where the oxygen combustion pipe is inserted into the fuel combustion pipe.
Hereinafter, the details of a purpose, a technical construction, a function, and an effect according to the present invention will be made clear by a description with reference to the accompanying drawings illustrating an exemplary embodiment of the present invention.
FIG. 1 is a cross-sectional view illustrating an eccentric jet type low NOX oxyfuel burner for gaseous fuel, according to the present invention, FIG. 2 is a left side perspective view illustrating an oxyfuel burner according to the present invention, FIG. 3 is a right side perspective view illustrating an oxyfuel burner according to the present invention, FIG. 4 is a left side cross-sectional view illustrating an oxyfuel burner according to the present invention, and FIG. 5 is a right side cross-sectional view illustrating an oxyfuel burner according to the present invention.
FIGS. 1 to 5 illustrate an eccentric jet type low NOX oxyfuel burner for gaseous fuel according to an embodiment in which a fuel combustion pipe is inserted into an oxygen combustion pipe.
The oxyfuel burner according to the present invention includes an oxygen combustion pipe 120 and a fuel combustion pipe 110.
The oxygen combustion pipe 120 is inserted within a burner tile 100 so as to be concentrically positioned with respect to the central axis of the burner tile 100, includes an oxygen feeding pipe 122 connected to one side portion of the circumferential surface thereof so that oxygen is supplied through an oxygen feeding inlet 123 provided at one end of the oxygen feeding pipe 122, and also includes an oxygen combustion nozzle 121 for injecting supplied oxygen, provided at one end thereof.
The fuel combustion pipe 110 is inserted within the oxygen combustion pipe 120 so as to be concentrically positioned respective to the central axis of the oxygen combustion pipe 120, includes a fuel feeding pipe 112 connected to one end thereof so that fuel is supplied through a fuel feeding inlet 113 provided at one end of the fuel feeding pipe 112, and also includes a fuel combustion nozzle 111 provided at the same side as the oxygen combustion nozzle 121 so as to inject fuel at a position deviating as much as a certain multiple of a set measurement from the central axis of the oxygen combustion pipe 120.
The burner tile 100 has an internally-penetrated cylindrical shape, and a fixing flange 101 is integrally provided at one end of the burner tile 100.
The oxygen combustion pipe 120 is inserted into the interior of the burner tile 100 in such a manner that the oxygen combustion pipe 120 has the same central axis as the burner tile 100 and also extends through the fixing flange 101, and a connecting part connecting the oxygen combustion pipe 120 with the fixing flange 101 is welded.
The oxygen feeding pipe 122 is connected to one side portion of the circumferential surface of the oxygen combustion pipe 120, and the oxygen feeding inlet 123 is provided at one end of the oxygen feeding pipe 122.
The oxygen combustion nozzle 121 for injecting oxygen supplied from the oxygen feeding inlet 123 is provided at one end of the oxygen combustion pipe 120.
A connecting flange 131 is provided at the other end of the oxygen combustion pipe 120, and a rotating flange 132 is provided at the connecting flange 131 so as to rotate while making contact therewith.
Herein, the rotating flange 132 is driven by a driving member 130 provided at one side of the connecting flange 131 so as to rotate, and the driving member 130 may use a known friction gear and includes a gear at the outer surface of the rotating flange 132 so that a driving gear to be engaged with the gear of the rotating flange 132 can be also used.
The fuel combustion pipe 110 is inserted into the oxygen combustion pipe 120 in such a manner that the fuel combustion pipe 110 has the same central axis as the oxygen combustion pipe 120. The fuel combustion nozzle 111 is provided at one end of the fuel combustion pipe 110 so as to inject fuel eccentrically from the center of the fuel combustion pipe 110.
Also, the fuel feeding pipe 112 is connected to the other end of the fuel combustion pipe 110 in such a manner that the fuel feeding pipe 112 is concentric to the central axis of the oxygen combustion pipe 120, and the fuel feeding inlet 113 is provided at one end of the fuel feeding pipe 112.
The rotating flange 132 rotates about the central axis of the oxygen combustion pipe 120 and is finish-welded to the fuel feeding pipe 112.
Herein, as the rotating flange 132 rotates, the fuel combustion pipe 110 rotates. A sliding connector 133 is provided at the fuel feeding pipe 112 so as to prevent the fuel feeding inlet 113 provided at one end of the fuel feeding pipe 112 connected to one end of the fuel combustion pipe 110 from rotating along with the fuel combustion pipe 110.
In other words, the fuel combustion pipe 110 is rotated within the oxygen combustion pipe 120 by the rotating flange 132. Therefore, the center of the fuel combustion nozzle 111 symmetrically moves from the center of the oxygen combustion pipe 120 while having a predetermined interval with it.
According to the above-described structure, a mixture rate between oxygen and fuel is different according to the area, and it can be achieved by the rotational movement of the fuel combustion nozzle 111.
In other words, in the area of the oxygen combustion nozzle 121, except the area of the fuel combustion nozzle 111, a mixture rate between oxygen and fuel is low. As such, as the fuel combustion nozzle 111 rotates within the oxygen combustion pipe 120, an injection-area of a low mixture rate is formed along the circumferential direction of the oxygen combustion nozzle 121 while moving along the direction opposite to the injection-area of the fuel combustion nozzle 111.
In other words, differently from a concentric injection type burner making a blue flame and a luminous flame symmetrically formed about the central axis of a nozzle according to the distance and direction of injection, a blue flame and a luminous flame are unsymmetrically formed about the central axis of a nozzle.
Therefore, the blue flame area with a high temperature is minimized, and the luminous flame area of a relatively low temperature is maximized. Accordingly, a flame temperature is wholly lowered so that the generation of a nitrogen oxide is restricted. Furthermore, the blue flame area with a high temperature is formed at the nozzle outlet of a burner so as to function as an ignition source, thereby maintaining the stability of the flame.

Claims

What is claimed is:

1. An eccentric jet type low NO_Xoxyfuel burner for gaseous fuel, comprising:

an oxygen combustion pipe inserted within a burner tile so as to be concentrically positioned respective to a central axis of the burner tile, the oxygen combustion pipe comprising an oxygen feeding pipe connected to one side portion of a circumferential surface of the oxygen combustion pipe so that oxygen is supplied through an oxygen feeding inlet provided at one end of the oxygen feeding pipe, and an oxygen combustion nozzle for injecting the supplied oxygen, provided at one end of the oxygen combustion pipe; and

a fuel combustion pipe inserted within the oxygen combustion pipe so as to be concentrically positioned respective to a central axis of the oxygen combustion pipe, the fuel combustion pipe comprising a fuel feeding pipe connected to one end of the fuel combustion pipe so that fuel is supplied through a fuel feeding inlet provided at one end of the fuel feeding pipe, and a fuel combustion nozzle provided at a same side as the oxygen combustion nozzle so as to inject fuel at a position deviating as much as a certain multiple of a set measurement from a central axis of the oxygen combustion pipe.

2. The eccentric jet type low NO_Xoxyfuel burner for the gaseous fuel as claimed in claim 1, wherein the fuel combustion pipe is capable of rotating about a central axis of the oxygen combustion pipe.

3. The eccentric jet type low NO_Xoxyfuel burner for the gaseous fuel as claimed in claim 2, wherein a rotating flange is driven by a driving means provided at one end of the oxygen combustion pipe so that the fuel combustion pipe rotates.

4. The eccentric jet type low NO_Xoxyfuel burner for the gaseous fuel as claimed in claim 1, wherein a center of the fuel combustion nozzle symmetrically moves while having a predetermined interval from a center of the oxygen combustion pipe.

5. An eccentric jet type low NO_Xoxyfuel burner for gaseous fuel, comprising:

a fuel combustion pipe inserted within a burner tile so as to be concentrically positioned respective to a central axis of the burner tile, the fuel combustion pipe comprising a fuel feeding pipe connected to one side portion of a circumferential surface of the fuel combustion pipe so that fuel is supplied through a fuel feeding inlet provided at one end of the fuel feeding pipe, and a fuel combustion nozzle for injecting the supplied fuel, provided at one end of the fuel combustion pipe; and

an oxygen combustion pipe inserted within the fuel combustion pipe so as to be concentrically positioned respective to a central axis of the fuel combustion pipe, the oxygen combustion pipe comprising an oxygen feeding pipe connected to one end of the oxygen combustion pipe so that oxygen is supplied through an oxygen feeding inlet provided at one end of the oxygen feeding pipe, and an oxygen combustion nozzle provided at a same side as the fuel combustion nozzle so as to inject oxygen at a position deviating as much as a certain multiple of a set measurement from a central axis of the fuel combustion pipe.

6. The eccentric jet type low NO_Xoxyfuel burner for the gaseous fuel as claimed in claim 5, wherein the oxygen feeding pipe is capable of rotating about a central axis of the fuel feeding pipe.

7. The eccentric jet type low NO_Xoxyfuel burner for the gaseous fuel as claimed in claim 6, wherein a rotating flange is driven by a driving means provided at one end of the fuel combustion pipe so that the oxygen combustion pipe rotates.

8. The eccentric jet type low NO_Xoxyfuel burner for the gaseous fuel as claimed in claim 5, wherein a center of the oxygen combustion nozzle symmetrically moves while having a predetermined interval from a center of the fuel combustion pipe.